As a forced compression type pump of this kind, "liquid and gas forced compression type pump" (Japanese Utility Model Application Publication Gazette No.55-184542) has been known.
Referring to FIG. 4, the above forced compression type pump includes a cylindrically shaped pump case A. an eccentric rotating body B shaft-supported on said pump case A at an eccentric position thereof and a compressing and forcibly sending member C which is movable in a radial direction of said eccentric rotating body B and is adapted to be brought into press contact with the interior wall of said pump case A, wherein said compressing and forcibly sending member C is composed of a rod-like roller 10 which is movable in a radial direction of said eccentric rotating body B and the volume of a forcibly sending member Q is reduced gradually from the inlet side 1 toward the outlet side 2 by rotation of said eccentric rotating body B so as to forcibly send gas or liquid.
In the above forced compression type pump which has already known, the difference in speed between the roller 10 and the roller support body 11 is big and accordingly the problem of much abrasion is involved.